(Original post by notnek)
You've made a mistake in your second line although it's hard to know for sure because your working isn't clear.

You cannot combine two logs which have different coefficients. In general,

oops, ib math exam tmrw and still stupid mistakes! ughh thx for pointing it out its like a warning before my exam tmrw that i gotta DOUBLE CHECK haha
shouldve been log_c a squared - log_c b = log_c a (squared) / b